public function __construct(Swift_Mime_HeaderSet $headers, Swift_Mime_ContentEncoder $encoder, Swift_KeyCache $cache, Swift_IdGenerator $idGenerator, $charset = null)
{
parent::__construct($headers, $encoder, $cache, $idGenerator, $charset);
$this->getHeaders()->defineOrdering(array('Return-Path', 'Received', 'DKIM-Signature', 'DomainKey-Signature', 'Sender', 'Message-ID', 'Date', 'Subject', 'From', 'Reply-To', 'To', 'Cc', 'Bcc', 'MIME-Version', 'Content-Type', 'Content-Transfer-Encoding'));
$this->getHeaders()->setAlwaysDisplayed(array('Date', 'Message-ID', 'From'));
$this->getHeaders()->addTextHeader('MIME-Version', '1.0');
$this->setDate(new DateTimeImmutable());
$this->setId($this->getId());
$this->getHeaders()->addMailboxHeader('From');
}